Water-soluble Form Research Articles

Distribution, sources and forms of mercury occurrence in the street dust of Mezhdurechensk (Kemerovo Region)

Abstract. The aim of this study was to investigate mercury concentration and forms of its occurrence in the dust component of the atmospheric air (street dust) to assess the geo-ecological condition of the area where coal is mined, processed and transported. The mean mercury concentration of 29 street dust samples collected along a uniform network throughout the city was 36.4 4.7 ng/g, with a minimum (4.6 ng/g) and a maximum (104.6 ng/g) value, respectively. This value was much lower than the mean concentration in soil samples taken previously at the same sites (58.4 ng/g) but higher than the mean concentration in snow solids (29.8 ng/g), which was likely due to precipitation that washed out mercury from the street dust and to the wind blowing. The method of successive chemical extraction revealed a weakly bonded water-soluble form, inorganic poorly sorbed mercury compounds, an organic form of mercury, and mercury associated with minerals. The proportion of each fraction accounted for on average 10.94%, 10.32%, 44.76%, and 33.97%, respectively. Water-soluble and acid-soluble mercury forms were less common. The bulk of mercury had metal-organic and sulfide forms. The study of mercury distribution based on particle size indicated that the mercury concentration increased as the diameter of the grains of dust material decreased. The fine fraction with a diameter of 20 to 50 m contained the bulk of mercury, which stayed in suspension form for a long time before settling on the surface.

Standard test method for mercury content evaluation in solid mineral fuels

Abstract. In addition to carbon, oxygen, hydrogen and nitrogen, fossil fuels contain other chemical elements, some of which may be hazardous to human health and the environment. Mercury and its compounds are one of the most dangerous among them. Therefore, information about mercury contents in coals and products of their processing is extremely important for both mining and processing enterprises and consumers. Mercury compounds may be accumulated in coal mining and processing wastes, and if they transfer into water-soluble forms, may lead to damaging of the environment. In the view of above, a standard method for the determination of mercury content has been developed, which is applicable not only to coals and products of their processing, but also to coal mining and combustion wastes. Also, to control the correctness of measurements by the developed method, reference samples with a certified mercury contents were developed.

Синтез и определение активности нового производного гидроксиоксопиримидина — потенциального объекта для изготовления противовоспалительного геля

Introduction. Compounds with a hydroxypyrimidine fragment in their structure exhibit pronounced and diverse biological activity. The low solubility of many hydroxypyrimidine derivatives in water is a significant drawback in the development of new medicines. From 5-butyl-6-hydroxy-2,3-diphenylpyrimidin-4(3H)-one, its water-soluble form being a sodium salt was obtained. This compound, as it was revealed during the computer screening of its possible biological acti¬vity in silico, can potentially be used as a pharmaceutical substance for the production (manufacture) of drugs. Since the line of hydroxypyrimidine drugs in the topical dosage forms is extremely limited, and the resulting compound has hydrophilic properties, it is important to enclose the substance in a gel dosage form. Aim. Synthesis of a water-soluble form of new hydroxypyrimidine derivative, determination of its acute toxicity and anti-inflammatory activity, as well as critical stages of development and further production of a topical hydrophilic dosage form based on the obtained compound. Materials and Methods. The target compound was obtained from the interaction of 5-butyl-6-hydroxy-2,3-diphenylpyrimidin-4(3H)-one and an equimolar amount of an aqueous solution of sodium hydroxide. Acute toxicity was determined on white mice (5 groups of 10 animals, which were injected with a solution of the study compound at a dose of 1100, 1200, 1300, 1400, and 1500 mg/kg respectively), observing the development of the main symptoms and recording the time of death of the animals within 72 h from the moment of the drug administration. For the experimental assessment of anti-inflammatory activity, two models were used: formalin-induced mice paw edema and cotton pellet implantation-induced granuloma in rats (for each model there were 3 groups with 10 animals per group: the 1st group received the reference drug diclofenac, the 2nd – the compound under study, the 3rd (control) – sodium chloride solution). Results. The yield of the obtained sodium 5-butyl-1,2-diphenyl-6-oxo-1,6-dihydropyrimidine-4-olate was 85 ± 1%. It has been proven in vivo that the test compound belongs to the 5th class of toxicity (practically non-toxic) and has a pronounced anti-inflammatory activity. An Ishikawa diagram was drawn up to determine the critical stages of the development and manufacture of a semisolid dosage form, a gel with a target substance. Conclusion. A new compound with anti-inflammatory action has been synthesized, sodium 5-butyl-1,2-diphenyl-6-oxo-1,6-dihydropyrimidin-4-olate, which has low toxicity and pronounced anti-inflammatory activity. The critical stages in the development and manufacture of a gel with synthesized compound are: preparation of the base and drug substance, introduction of the drug substance into the base, homogenization and packaging.

Influence of different doses of fertilizers on significant traits of soybean cultivar "Lira"

This article presents the results of a study conducted in 2021 in the experimental field of the Federal Scientific Vegetable Center in the Moscow Region. The effect of fertilizer application on various significant traits of the early soybean cultivar Lira was studied. For our study, we used a complex water-soluble fertilizer Universal brand 18:18:18+ 3 MgO + ME (LC “Voskresensk Mineral Fertilizers”), containing an equal amount (18%) of water-soluble forms of nitrogen, phosphorus and potassium, an easily accessible form of magnesium and the six most important trace elements (boron, copper, iron, manganese, molybdenum, and zinc). The effect of fertilizer was studied according to the following scheme: Control (K, 0 g/m2 of fertilizer), Variant 1. - 0.5 g/m2 of fertilizer (B1), Variant 2. - 1 g/m2 of fertilizer (B2) and Variant 3. - 1.5 g/m2 of fertilizer (B3). It was found that the application of fertilizer had a significant effect (Ff < F05) on the traits we studied (plant height, lower pod attachment height, weight of 1000 seeds, number of pods and seeds per 1 soybean plant). Regarding plant height and lower pod attachment height, a negative effect of fertilizer application was revealed, as we observed a decrease in plant height by 4.7%, 16.2% and 18.3% for variants 1, 2 and 3, respectively; and a decrease of lower pod attachment height of 21.9%, 18.4%, and 17.0% for these variants. The application of fertilizers contributed to an increase in the number of pods by 5–26 pcs/plant, the number of seeds per plant by 7–51 pcs/plant. compared to control. The application of fertilizers also increased the weight of 1000 seeds by 10.15–32.12 g. Among the studied variants, the second variant - B1 (0.5 g/m2) had the most effect on the studied traits.

The first data regarding the effect of the exotic Eisenia ventripapillata (Oligochaeta, Lumbricidae) on the cation composition of soils in Western Siberia

We have performed laboratory experiments to determine the impact of earthworms (exotic Eisenia ventripapillata and peregrine Aporrectodea caliginosa) on the water-soluble forms of ammonium, potassium, sodium, magnesium, calcium in Calcic Chernozem, Greyic Phaeozem, and Haplic Chernozem, which are widespread in the south of Western Siberia. The differences between the impacts made by the two above-mentioned species have been estimated according to the changes they make in the initial cation concentrations in soil. For E. ventripapillata, the obtained evidence regarding the influence of this species on soil characteristics is first-ever data. We found that E. ventripapillata and A. caliginosa changed the content of all cations in the soils under this study, but the nature of these changes varied from one soil type to another. In contrast to A. caliginosa, E. ventripapillata reliably increased the content of potassium and calcium ions in Calcic Chernozem. In comparison with the A. caliginosa influence, the E. ventripapillata variants reliably differed in the content of ammonium, potassium, and sodium ions in Greyic Phaeozem. In Haplic Chernozem, the ammonium, magnesium, and sodium ions content in the E. ventripapillata variants was reliably lower than in the A. caliginosa variants. Thus, the observed difference between native and exotic species in the effects on the content of available cations can trigger changes in the mineral nutrition of plants growing in the examined soils. The article contains 2 Figures, 1 Table and 49 References

New water-soluble forms of α-tocopherol: preparation and study of antioxidant activity in vitro

Water-soluble forms of α-tocopherol (vitamin E) possessing antioxidant activity in vitro were obtained by encapsulating in N-vinylpyrrolidone with triethylene glycol dimethacrylate polymer particles and were characterized by various physicochemical methods. Quantum-chemical modeling of a structure of α-tocopherol with the copolymer moiety and its theoretical absorption spectra modeling were carried out.

Synthesis of a hydrophilic derivative of ecdysterone and development of its water-soluble form

The article presents materials on the isolation of ecdysterone substance from medicinal plant raw materials Silene wolgensis (Hornem.) Bess. ex. Spreng (Volga smolyovka). For the first time, the optimization of the method for ecdysterone substance obtaining from the aboveground part of the superconcentrator of phytoecdysteroids of the Silene wolgensis was carried out and based on it a pilot industrial regulation for the isolation of ecdysterone and an encapsulated water-soluble form were developed. It was found, that the interaction of the substrate molecule and the clathrate forms a substance that can dissolve in water and other more polar solvents, thereby solving the problem of bioavailability of the main hydrophobic drug. The method developed for producing the substance ecdysterone and its water-soluble encapsulated with β-cyclodextrin form was implemented into production at the Karaganda pharmaceutical plant. NMR studies of changes in the chemical shifts of protons of substrates and receptors illustrated that ecdysterone interacts with β-cyclodextrin to form supramolecular inclusion complexes with stoichiometric composition of 1:1

Форми знаходження урану і радіонуклідів у донних відкладеннях приміщення 001/3 об’єкта «Укриття»

The results of experimental determination of the forms of uranium and radionuclides 90Sr, 137Cs, 154Eu, 238Pu, 239+240Pu, 241Am, and 244Cm in the bottom sediments of the premises 001/3 of the "Shelter" object are presented. By the sequential extraction procedure, the following amounts are determined: water-soluble, exchange, carbonate, and acid-soluble forms of uranium, fission products (90Sr, 137Cs, 154Eu), and transuranium elements (238Pu, 239+240Pu, 241Am, 244Cm) in the bottom sediments in the premises 001/3 on a mark of -2.60 m of auxiliary systems of the reactor compartment of the "Shelter" object. The concentration of uranium in the bottom sediments of room 001/3 is 3.1 ± 0.5 g/kg. Specific activity of 90Sr, 137Cs in the bottom sediments is within the range of 6·108 - 1·109 Bq/kg, and 239+240Pu and 241Am within the range of 6·105 - 8·106 Bq/kg. Radionuclides 90Sr, 137Cs, 154Eu, 238Pu, 239+240Pu, 241Am, 244Сm in the bottom sediments are in different chemical forms that will define their different potential mobility. Uranium and 137Cs in the bottom sediments of premises 001/3 mainly are in exchange forms. The amount of water-soluble forms of uranium and cesium is 1.5 - 3 %. The basic amount of 90Sr, more than 60 %, is carbonate soluble in a weak acid at рН 4.8. More than 65 % of 238Pu and 239+240Pu in the bottom sediments are in acid-soluble forms. The mobility of 154Eu, 241Am and 244Cm in the bottom sediments is much higher than that of plutonium; at pH 4.8 more than 40 % of 241Am go to soluble state. The ratio between the activities of 137Cs/90Sr, 90Sr/239+240Pu, 241Am/239+240Pu, and 244Cm/239+240Pu in the bottom sediments considerably differ from the analogical relations of radionuclides in a fuel containing materials of the "Shelter" object.

ГЕОХІМІЧНА ТРАНСФОРМАЦІЯ ОБ’ЄКТІВ ДОВКІЛЛЯ В МЕЖАХ ПОЛІГОНІВ ЗАХОРОНЕННЯ ТВЕРДИХ ПОБУТОВИХ ВІДХОДІВ (НА ПРИКЛАДІ МІСТА КИЄВА)

The presented research is devoted to the study of geochemical transformation of environmental key objects (soils, surface and groundwater) within the solid waste landfills. The object of the study is the one of the largest landfills for solid waste disposal in Ukraine – Kyiv landfill №5. The main factual material, which is the basis of the article, was obtained by the authors during a comprehensive field ecological and geochemical research in 2018-2020. The aim of the work was to determine the geochemical (in particular physical and chemical) features of soil sediments within the landfill, which made it possible to assess the protective properties of soils in relation to the impact of technogenic metals. The condition of surface waters (ponds within the landfill territory) and groundwater (wells in Pidhirtsi village) was also studied; the comparison of the main indicators of chemical composition with the maximum allowable concentrations determined by normative documents was performed. It was found that in the studied soils there is a high concentration of heavy metals associated with the fraction of easily exchangeable ions, as well as an increased content of water-soluble forms. The main migration forms of macro- and microelements in soil solutions have been established. It was found that free hydrated cations and metal-organic complexes are characteristic of heavy metals. For groundwater used for potable water consumption by the population of Pidhirtsi village, exceeding of maximum allowable concentrations were recorded for certain indicators, in particular for nitrates, as well as deviations from the established norms for Ba, SO4, Fe, Mn, Co, Ni, Mo, and Pb. The pond waters, located directly within the landfill territory, are characterized by significant deviations from the norm in terms of Fe, Mn, Ni, Ti, V, Cu and Zn. As a result of the study, it was found that within the landfill there are favorable conditions for the formation of mobile forms of toxic elements and their migration to surface and groundwater

How the Chemical Properties of GBCAs Influence Their Safety Profiles In Vivo.

The extracellular class of gadolinium-based contrast agents (GBCAs) is an essential tool for clinical diagnosis and disease management. In order to better understand the issues associated with GBCA administration and gadolinium retention and deposition in the human brain, the chemical properties of GBCAs such as relative thermodynamic and kinetic stabilities and their likelihood of forming gadolinium deposits in vivo will be reviewed. The chemical form of gadolinium causing the hyperintensity is an open question. On the basis of estimates of total gadolinium concentration present, it is highly unlikely that the intact chelate is causing the T1 hyperintensities observed in the human brain. Although it is possible that there is a water-soluble form of gadolinium that has high relaxitvity present, our experience indicates that the insoluble gadolinium-based agents/salts could have high relaxivities on the surface of the solid due to higher water access. This review assesses the safety of GBCAs from a chemical point of view based on their thermodynamic and kinetic properties, discusses how these properties influence in vivo behavior, and highlights some clinical implications regarding the development of future imaging agents.

Sorption Properties of ZrO2-Analcime Composites in Relation to Cs(I) and Sr(II)

Composite zeolite sorbents based on analcime with inclusions of hydrated zirconium dioxide (ZrO2-analcime) have been obtained by hydrothermal treatment of coal fly ash cenospheres with a high glass phase content in the presence of a zirconium compound and an alkaline activating agent at 150 °C and different stirring modes of the reaction mixture. The synthesis products were characterized by XRD, SEM-EDS, STA and low-temperature nitrogen adsorption; their sorption properties with respect to Cs+ and Sr2+ were studied in the pH range of 2–10. It was found that the ZrO2-analcime compositions surpass unmodified analcime by 2–5 times in terms of sorption of Cs+ and Sr2+ and by two orders of magnitude in terms of the distribution coefficient value (KD ~106 ml/g). The process of high-temperature solid-phase transformation of Cs+/Sr2+-exchanged forms of the compositions was studied, which simulates the process of conversion of water-soluble forms of Cs‑137 and Sr‑90 radionuclides into a mineral-like form. It was shown that at 1000 °C the ZrO2-analcime compositions with sorbed Cs+ and Sr2+ undergo the phase transformation resulting in polyphase systems of similar composition based on nepheline, tetragonal ZrO2, and glass phase

Secondary Malnutrition and Nutritional Intervention in Cholestatic Liver Diseases in Infants.

We aimed to conduct an updated review on the pathophysiology, diagnosis, and nutritional intervention of CCLD and secondary malnutrition in infants. Protein-energy malnutrition, impaired linear growth, fat-soluble vitamin deficiencies, and hepatic osteodystrophy can occur in up to 80% of cases. The proposed pathophysiological mechanisms include insufficient energy intake, lipid- and fat-soluble vitamin malabsorption, increased energy expenditure, altered intermediate metabolism, hormonal dysregulation, and systemic inflammation. The current approach to diagnosis is the identification of the deviation of growth parameters, body composition, and serum concentration of micronutrients, which determines the type and magnitude of malnutrition. Currently, liver transplantation is the best therapeutic alternative for the reversal of nutritional impairment. Early and effective portoenteroanatomosis can extend survival in patients with biliary atresia. Medical and dietary interventions in some storage and metabolic diseases can improve liver damage and thus the nutritional status. A proportion of patients with biliary atresia have fat-soluble vitamin deficiencies despite receiving these vitamins in a water-soluble form. With aggressive enteral nutrition, it may be possible to increase fat stores and preserve muscle mass and growth. The nutritional issues identified in the pre- and post-transplantation stages include muscle mass loss, bone demineralization, growth retardation, and obesity, which seems to correspond to the natural history of CCLD. Due to the implications for the growth and development of infants with CCLD with this complex malnutrition syndrome, innovative projects are required, such as the generation of prediction and risk models, biomarkers of growth and body composition, and effective strategies for nutritional prevention and intervention.

EXTH-57. EFFICACY OF SOLUBLE PANOBINOSTAT (MTX110) IN PRECLINICAL MODELS OF ADULT GLIOBLASTOMA

Abstract INTRODUCTION One of the biggest challenges in treating glioblastoma is achieving effective local drug concentrations, and trials using systemic administration of therapeutics have failed in GBM despite compelling pre-clinical evidence. MTX110 (Midatech Pharma PLC) is a water-soluble form of panobinostat currently in clinical development for DIPG and medulloblastoma using direct tumor delivery. We have previously reported a significant positive benefit of MTX110 in a subcutaneous GBM mouse model in an IDH1 mutated cell line. Here we present follow on data on the potential for MTX110 synergy with radiation in pre-clinical in vivo models. We also present data on efficacy of MTX110 in a panel of GBM cell lines. METHODS In vitro: Cell lines were incubated with MTX110 for 72h over a range of concentrations (1nM-10µM). Each concentration was tested in triplicate with the appropriate blank controls included in each plate. After 72 hours, cell viability was measured via luminescence signal (Promega CellTiter-Glo Luminescent Cell Viability Assay kit (Promega-G7573) read via 2104 EnVision Multilabel Reader, PerkinElmer. In vivo: Tumor-bearing mice were stratified to either the vehicle control or treatment group based on median tumor volume and were treated with MTX110 at a dose of 15mg/kg IP, 5 days consecutively for 2 consecutive weeks, following radiation treatment at a dose of 4Gy delivered as a single fraction on day 1. RESULTS In vitro, MTX110 demonstrated cytotoxic activity in 4 GBM cell lines (U87MG, U251MG, U118MG and T98G) with an average IC50 value in the region of 40nM (17-43nM). In vivo MTX110 in combination with radiation treatment showed an enhanced delay in tumor growth of approximately 50% compared to MTX110 or radiation alone. The results are supportive of the planned exploratory trial in GBM with MTX110.

Arsenic and metal quantities in abandoned arsenide tailings in dissolved, soluble, and volatile forms during 20 years of storage

In this study, the risk of environmental pollution by arsenic (As) and heavy metals from the tailings of Co-Ni arsenide ores at the Khovu-Aksy mine site (Russia) has been systematically evaluated over 20 years. The assessment results indicated that As poses the greatest concern, followed by Cu, Zn, Co, and Ni, among others.This article presents the results of a study on the mobile forms of metals (Cu, Ni, and Co, among others) and metalloids (e.g., As and Sb) in stored waste that was produced by the hydrometallurgical processing of Cu–Co–Ni arsenide ore from the Khovu-Aksy deposit. A comparative assessment of the changes in element forms during the 20-year of waste storage period was conducted. It was determined that in the pore solutions, the metal concentration decreased by an average of 7–10 times because they precipitated into secondary solid phases or were adsorbed on sulfides. Moreover, the As concentrations in the pore solutions remained practically unchanged, and in some cases, they slightly increased, i.e., this element remained immobile. In contrast, greater changes occurred in the fractional composition of the element forms, which were determined based on the compositions in water extracts. The concentrations of the water-soluble forms of the metals decreased by 100–700 times in 20 years. The concentrations of the soluble As compounds decreased by 1.6–4.6 times. A study of the mineralogy of the tailings showed that the secondary rims of the Fe hydroxides and Ca carbonates with admixtures of Cu, Zn, Co, Ni, and Ag formed on the grains of the sulfide and arsenide grains. The secondary As compounds on the rims are represented by aqueous Fe arsenate. The obtained data indicate active processes of metal deposition, while As remained mobile. The internal structure and geometries of the groundwater horizons were determined by using electrical resistivity tomography, which made it possible to calculate the quantities of dissolved metals and metalloids in the tailings. Condensates were collected to determine the concentrations of the volatile forms of the elements, and the amounts migrating with the vapor–gas flows were estimated. At present, the tailings contain ~2.1 tons of dissolved As (in pore water), ~ 85 tons of soluble As (in water-soluble forms), and ~ 23 kg of volatile As that enters the air with vapor–gas flows during summer.

Effects of magnetically treated Sedum alfredii seeds on the dissolved organic matter characteristics of Cd-contaminated soil during phytoextraction.

The effects of magnetic field treatments on the two determining factors of phytoremediation, growth status and element uptake capacity, of Sedum alfredii Hance. have been thoroughly studied; however, minimal studies have been performed to determine the influence of the Cd hyperaccumulator S. alfredii, grown from magnetically treated seeds, on the dissolved organic matter (DOM) characteristics in its rhizosphere. A series of pot experiments were conducted to evaluate the variations in the DOM concentration and fractionations in the rhizosphere of S. alfredii treated with external magnetic fields. Compared with the untreated seeds, S. alfredii grown from magnetically treated seeds excreted more DOM in its rhizosphere. Additionally, the hydrophilic DOM fractionation proportion, which presented a greater capacity to mobilize Cd in the soil, increased from 42.7 % in the control sample to 47.2 % in the 150 mT magnetically treated S. alfredii sample. The water-soluble and exchangeable forms of Cd in the rhizosphere of the magnetically treated S. alfredii were significantly lower than those of the control sample. Furthermore, the Cd extraction capacity of DOM from the rhizosphere of the magnetically treated S. alfredii was greater than that of the control sample, thereby increasing the Cd uptake ability of the magnetically treated species. This study proves that a suitable magnetic field treatment can enhance the phytoremediation effect of S. alfredii, and reveals the mechanism of the phenomenon from the perspective of changes in soil DOM.

Do freeze-thaw cycles affect the cadmium accumulation, subcellular distribution, and chemical forms in spinach (Spinacia oleracea L.)?

To date, although there are many studies investigating the toxicity of heavy metal to plant, little research exists in the seasonal freeze-thaw (FT) regions where FT cycles often happen during the plant growing process. To reveal the adaptive mechanisms of plants to the combination stresses of cadmium (Cd) and FT, the Cd accumulation, subcellular distribution, chemical forms, and antioxidant enzyme activity (peroxidase (POD)) were investigated in spinach (Spinacia oleracea L.) growing under different soil Cd levels (i.e., 0.10 mg Cd kg−1 soil (low), 1.21 mg Cd kg−1 soil (medium), and 2.57 mg Cd kg−1 soil (high)). Compared to the non-freeze-thaw (NFT) treatments, higher Cd concentrations in the root and lower translocation factors from root to leaf were found for the plants experiencing FT cycles. FT significantly decreased the Cd concentrations in the leaves under the low- and medium-Cd treatments, while similar values were found for the high-Cd treatments. Generally, FT could decrease the concentrations and proportions of Cd stored in the cell wall and soluble fractions and increase them in the organelle fractions for the medium- and high-Cd treatments, while opposite tendency was found for the low-Cd treatments. Moreover, larger Cd amounts in the inorganic and water-soluble forms were found for the low- and medium-Cd treated plants under FT, while lower values were found for the high-Cd treatments. Additionally, POD, which presented higher activities at the low- and medium-Cd treatments and lower activities at the high-Cd treatments under FT, were also significantly influenced by the Cd × FT interaction. This study indicated that FT could significantly change the accumulations of Cd in plant, and it provided a new insight into the Cd accumulation by plants in the seasonal FT region.

Toxicology and carcinogenesis studies of sodium tungstate dihydrate in Sprague Dawley (Hsd:Sprague Dawley SD) rats and B6C3F1/N mice (drinking water studies).

Sodium tungstate dihydrate (ST) is present naturally in the environment and can enter waterways through the weathering of rocks and soils. ST also is a high-production volume compound that is used in a variety of commercial applications including fire- and waterproofing fabrics, in the preparation of complex compounds (e.g., phosphotungstate and silicotungstate), as a reagent for biological products, and as a precipitant for alkaloids. Tungsten was nominated to the National Toxicology Program (NTP) by the Centers for Disease Control and Prevention to evaluate its potential to cause chronic toxicity and carcinogenicity because of concern about potential human exposure via contaminated drinking water (e.g., in the form of salts like tungstate) and inadequate data to assess human health implications of elevated exposures. ST was selected for study because it is the most prevalent water-soluble form of tungsten. In these studies, Sprague Dawley (Hsd:Sprague Dawley SD) rat dams were exposed to ST in drinking water from gestation day (GD) 6 through lactation day (LD) 20. Their pups were exposed to the same exposure concentrations in drinking water from postnatal day (PND) 12 through 3 months or 2 years. Adult male and female B6C3F1/N mice were exposed to ST in drinking water for 3 months or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, Escherichia coli, rat and mouse peripheral blood erythrocytes, and cells from liver, kidney, and ileum; peripheral blood leukocytes from rats and mice also were assessed for DNA damage. (Abstract Abridged).

Potassium regime in postagrogenic soils that came out of cultivation at different time periods and are currently at different vegetation cover succession stages

We present the results of a study of the potassium regime of postagrogenic soils at different stages of vegetation recovery carried out in the Leningrad region, Russia. The objects of the study were sites with meadow-shrub vegetation and young deciduous stands with regeneration of pine and spruce on postagrogenic soils formed on two-member sediments. For agrochemical analysis, soil samples were taken from an arable (0-20 cm) and underlying (20-40 cm) horizons. The content of available forms of mobile potassium correlated more closely with the soil pH at the beginning of the growing season than at the end of it. With a decrease in elevation, both the content of mobile forms of potassium and soil acidity increased, which was associated both with the migration of potassium forms along the soil profile and with the granulometric composition of soils. Potassium in the sandy loam horizon of the soil was the most mobile, in contrast to that in the light loamy former arable horizon. With age, under vegetation developing on postagrogenic soils on two-member sediments, an accumulation of both water-soluble and mobile forms of potassium in the former arable horizon can be observed, which indicates restoration of soil fertility.

Water-soluble components of soils on calcareous rocks in the Polar Urals

A comparative analysis of the chemical composition and features of the water-soluble part of soils on calcareous rocks in the Northern part of the Bolshoi Paipudynskii Ridge (Polar Urals) was carried out. In the studied soils, significant differences in the content of water-soluble forms of organic carbon (5-80 g/kg), nitrogen (0.2-3.7 g/kg) and the amount of cations of readily soluble salts (1.5-32 g/kg) are largely determined by the phytocenotic factor (composition and structure of plant communities) and the influence of relief (steepness of slopes, nature of moistening). The surface horizons of soils that consist of the plants’ remains from the fall of previous years largely inherit the specific features of aboveground biomass. Moreover, they are characterized by minimal pHH2O values, accumulation of soluble organic forms C and N, and readily soluble salts. The concentration of cations in the composition of soluble compounds decreases significantly with depth. Regardless of the soil genesis, calcium cations (80-90%) and alkalinity-determining ions (80-97%) dominate in extracts from mineral horizons. Obtained data can be used to predict the behavior of elements in the soil and landscape, as well as for the balance calculation of carbon and nitrogen cycles.

Extraction of Rubidium Element from Malatya - Kuluncak Area Complex Ore

In this study, studies were carried out to take into solution the element rubidium (Rb), which is in the complex ore structure of Na + K feldspar, pyroxene and alumina silicate, in an environmentally sensitive manner with high efficiency. Malatya - Kuluncak complex was used in the study. In the first stage of the study, the roasting method was tried to obtain rubidium chloride (RbCl) or rubidium sulphate (Rb2SO4) structures, which are the water-soluble forms of rubidium in the sodium-potassium feldspar structure. Roasting was carried out using different additives and it was seen that the most suitable additive material for this ore structure was calcium chloride. In studies investigating the effect of roasting temperature and time, the RbCl evaporation amount was calculated. After deciding on the additive material, additive amount, solid / liquid ratio in extraction stage and extraction time were optimized. The optimum conditions were determined as an extraction time of 120 minutes at 1/3 solid / liquid ratio after roasting for 60 minutes at a roasting temperature of 900 °C at %70 calcium chloride (CaCl2) addition and the solution efficiency of rubidium was calculated as 96%. In this study, it was the first time to take Rb into solution from primary sources with high efficiency in Turkey.